From owner-freebsd-hackers@freebsd.org  Tue Jul  5 11:45:25 2016
Return-Path: <owner-freebsd-hackers@freebsd.org>
Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 0AB1FB21E74;
 Tue,  5 Jul 2016 11:45:25 +0000 (UTC)
 (envelope-from gahr@FreeBSD.org)
Received: from mail.ptrcrt.ch (gahr.cloud.tilaa.com [84.22.109.158])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id 5EF211C9F;
 Tue,  5 Jul 2016 11:45:22 +0000 (UTC)
 (envelope-from gahr@FreeBSD.org)
Received: from webmail.ptrcrt.ch (www.gahr.ch [192.168.1.2])
 by mail.ptrcrt.ch (OpenSMTPD) with ESMTPSA id c381a7a4
 TLS version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO;
 Tue, 5 Jul 2016 11:45:14 +0000 (UTC)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII;
 format=flowed
Content-Transfer-Encoding: 7bit
Date: Tue, 05 Jul 2016 13:45:13 +0200
From: Pietro Cerutti <gahr@FreeBSD.org>
To: Willem Jan Withagen <wjw@digiware.nl>
Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org>,
 owner-freebsd-hackers@freebsd.org
Subject: Re: Problem during dlopen()
Organization: The FreeBSD Project
In-Reply-To: <5e29e535-f91f-35fb-2a7e-324bb19b658f@digiware.nl>
References: <5e29e535-f91f-35fb-2a7e-324bb19b658f@digiware.nl>
Message-ID: <416028b6b2a1dffe4e010b5792c56100@gahr.ch>
X-Sender: gahr@FreeBSD.org
User-Agent: Roundcube Webmail/1.2.0
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
 <freebsd-hackers.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/freebsd-hackers>, 
 <mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers/>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
 <mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 05 Jul 2016 11:45:25 -0000

On 2016-07-05 13:13, Willem Jan Withagen wrote:
> Hi,
> 
> I'm banging my head agains the wall because I cannot seem to get this
> working.
> 
> The problem is due to changing from automake to cmake building.
> 
> But all my dlopens start failing with something like:
> load failed dlopen(build/lib/compressor/libceph_snappy.so) or
> dlopen(build/lib/libceph_snappy.so): build/lib/libceph_snappy.so:
> Undefined symbol "_ZN4ceph6buffer4list8iterator7advanceEl"
> 
> If do a lookup for  the name:
> nm build/lib/libceph_snappy.so |grep 
> ceph6buffer4list8iterator7advanceEl
> 
> if give me:
>                  U _ZN4ceph6buffer4list8iterator7advanceEl
> 
> The parent/calling executable however has:
> 	0000000000513de0 T _ZN4ceph6buffer4list8iterator7advanceEl
> 
> Clearly dlopen is not able to match these 2 and succeed.
> 
> Question:
> So on which part of the building is what switch missing.

Wild guess: -Wl,-E linking the executable.

-- 
Pietro Cerutti
gahr@FreeBSD.org

PGP Public Key:
http://gahr.ch/pgp